Tearing mode instability due to anomalous resistivity near edge

Tearing mode instability in the presence of microscopic turbulence is inves tigated. The effects of microscopic turbulence on tearing mode are taken as drags which are calculated by one-point renormalization method and mean-fi eld approximation. These effects are reduced to effective diffusivities in reduced MHD equations. Using these equations, the stability analyses of the tearing mode are performed. It is shown that a finite amplitude of fluctua tion enhances the growth rate of tearing mode. For very high values of turb ulent diffusivities, marginally stable state exists. The effects of each tu rbulent diffusivity on mode stability are examined near marginal stability boundary. Parameter dependence of the resistive ballooning mode turbulence on tearing mode is analyzed as an example.